$(document).ajaxSend(function(e,xhr,opt){
    var token = localStorage.getItem("user_token");
    xhr.setRequestHeader("user_token_header",token);
});
function logout(){
 
    // var r= confirm("这样写可以直接显示,不接收返回值。");

    
        localStorage.removeItem("user_token");
        location.href = "blog_login.html";
   

   
}